As terminal devices (e.g., smartphones) are becoming popular, applications in them are also becoming increasingly varied and plentiful. Many users like to interact with terminal devices by, for example, viewing a webpage or playing a video, with a browser, a player, or a reading-related application, among other things. Users are more and more aware of the importance of protecting their privacy during interacting with terminal devices, especially when their demands are multifaceted and personal. For instance, when a user is working or doing some other secret things on a terminal device, the user does not hope for another person (e.g., one of his colleagues, or his child) who suddenly appears before him to see what he is watching on the terminal device.
In the relevant technologies, it is usual to provide a terminal device with a privacy screen or to stick a privacy film on the screen of a terminal device. Also, there are other peep-proof methods, including quick exit, page minimization and page closing. However, when a privacy screen or privacy film is employed, the user may find, besides the unhidden sound, that the screen turns darker, because a privacy screen or privacy film achieves the peep-proof purpose by shielding off light in certain directions. In addition, the thickness of a privacy film might sometimes make the touch screen insensitive. In the case of quick exit, page minimization, or page closing, it may take the user too long a time to disappear the viewed page quickly enough in an unexpected situation, and it may also be inconvenient for the user to return to the previously viewed page in order to continue the previous work or operation.